Leukocyte differential and reactive lymphocyte counts from Sysmex XN analyzer in the evaluation of SARS-CoV-2 infection

Extended Inflammation Parameters (EIP) as Markers of Inflammation in Systemic Sclerosis

Background

Systemic sclerosis (SSc) is an autoimmune disease characterized by inflammation, progressive vasculopathy, and fibrosis of skin and internal organs. The aim of the study was to evaluate extended inflammatory parameters (EIP) in patients with SSc in comparison to the control group of healthy subjects.

Methods

A total of 28 patients with SSc and 29 healthy controls (HCs) were included in the study. The following EIP parameters were analyzed: neutrophil reactive intensity (NEUT-RI), neutrophil granularity intensity (NEUT-GI), antibody-synthesizing lymphocytes (AS-LYMP), and reactive lymphocytes (RE-LYMP).

Results

Patients with SSc showed significantly higher values of parameters determining neutrophil reactivity and neutrophil granularity when compared to HCs (respectively, 49.16 FI vs. 44.33 FI, p < 0.001, and 152.01 SI vs. 147.51 SI, p < 0.001). Moreover, patients with SSc had higher absolute numbers of RE-LYMP than HCs (0.69 × 103/µl vs. 0.04 × 103/µl, p < 0.001). Importantly, significant correlations between the RE-LYMP and either IL-6 (R = 0.447, p < 0.001) or ESR (R = 0.532, p < 0.001) were found among patients with SSc.

Conclusions

Changes in NEUT-RI, NEUT-GI, and RE-LYMP levels positively correlate with inflammation in SSc and, thus, could potentially be used as an additional reliable inflammatory biomarker to assess inflammation in this disease.

RNA Sequencing in COVID-19 patients identifies neutrophil activation biomarkers as a promising diagnostic platform for infections

Infection with the SARS-CoV2 virus can vary from asymptomatic, or flu-like with moderate disease, up to critically severe. Severe disease, termed COVID-19, involves acute respiratory deterioration that is frequently fatal. To understand the highly variable presentation, and identify biomarkers for disease severity, blood RNA from COVID-19 patient in an intensive care unit was analyzed by whole transcriptome RNA sequencing. Both SARS-CoV2 infection and the severity of COVID-19 syndrome were associated with up to 25-fold increased expression of neutrophil-related transcripts, such as neutrophil defensin 1 (DEFA1), and 3-5-fold reductions in T cell related transcripts such as the T cell receptor (TCR). The DEFA1 RNA level detected SARS-CoV2 viremia with 95.5% sensitivity, when viremia was measured by ddPCR of whole blood RNA. Purified CD15+ neutrophils from COVID-19 patients were increased in abundance and showed striking increases in nuclear DNA staining by DAPI. Concurrently, they showed >10-fold higher elastase activity than normal controls, and correcting for their increased abundance, still showed 5-fold higher elastase activity per cell. Despite higher CD15+ neutrophil elastase activity, elastase activity was extremely low in plasma from the same patients. Collectively, the data supports the model that increased neutrophil and decreased T cell activity is associated with increased COVID-19 severity, and suggests that blood DEFA1 RNA levels and neutrophil elastase activity, both involved in neutrophil extracellular traps (NETs), may be informative biomarkers of host immune activity after viral infection.